let hname: string = "好学生";
hname = "666";
const nn: string = "第三方的";
n = "888";
let age: number = 37;
age = 37;
const age1: number = 37;
age1 = 22;
let wk: boolean = false;
wk = true;
let list111: number[] = [1, 2, 3];
list = [2, 2, 2];
let list11: Array<number> = [1, 2, 3];
let w: null = null;
let kkl: undefined = undefined;
function User(): void {
	console.log("This is my warning message");
}
const ob: object = { "w": 22 };
const obj: object = { "w": 1, "e": 2, "r": 3 };
function addwk(x: number, y: number): number {
	return x + y;
}
addwk(1, 2);
function swk(x: string, y?: string): string {
	return x + y;
}
swk("wk", "ww");
function wk1(x: string, y?: string, z?: string): string {
	return x + y + z;
}
function mname(x: string, y: string, z?: string): string {
	if (z) {
		return x + y + z;
	}
	return x + y;
}
function buildName(firstName: string, lastName = "Smith") {
	return firstName + " " + lastName;
}
function nname(x: string, ...y: string[]) {
	return x + " " + y.join(" ");
}
function qqq(x: string, y: string | number) {
	return x + y;
}
qqq("qq", "qq");
function sun(x: string | number, y: string | number) {
	if (typeof x === "number" && typeof y === "number") {
		return x + y;
	} else {
		return x.toString() + y.toString();
	}
}